The sole aim of this book is to convince our readers about the validity of a new four-dimensional (4D) model of physics justifying the existence of fourth space dimension. Due to the presence of an extra space dimension, this 4D space model is totally different from the standard model of particle physics. Standard model accepts the hypothesis of expanding universe with big bang origin disregarding the problem of singularity at the origin. However our new model accepts an alternate singularity-free cosmology and everyone will be surprised to know that theories and equations obtained from this new cosmology are able to give simple explanations of many puzzles of physics such as: internal structure of fundamental particle, origin of mass, origin of charge, origin of spin, origin of strong force, wave- particle duality of matter and radiation and many others. Five Important Features of the New Model: 1. Our 3D universe is the intersection of two 4D universes, filled with two kinds of 4D particles. Every phenomenon, that we observe, is the projection of a 4D phenomenon on a 3D base (our 3D universe). 2. Photon-energy is utilized to create fundamental particles from these 4D particles in a 4D reversible process, roughly similar to the 3D spiral process of pot making on a rotating pad. 3. Repulsive Coulomb force becomes attractive strong force as point of contact of interacting particles passes over the point of inflexion, where concavity or convexity changes sign. 4. Schrödinger equation and de Broglie hypothesis can be derived from 4D wave pulse of fundamental particle 5. Nearly twenty fundamentals of modern physics, which can be (or cannot be) explained by quantum concepts of standard model, are explained by 4D classical picture of our new model. (Physics community is requested to verify the truth behind this feat of the new model before accepting it.)